Remote access: Have it your way

In the remote access arena, the more things change, the more they stay the same. Vendors continue to increase port capacity, improve security and beef-up fault tolerance. While buyers' options increase, however, the fundamental technology behind today's remote access devices remains largely as it was last year.

From a network manager's standpoint, traditional direct-dial remote access has a lot going for it. It's familiar, it's relatively easy to implement and it uses standard communications software. The newest direct-dial remote access gear supports hundreds of users on a single chassis without the banks of individual modems and the nest of wiring we saw just a few years ago. Instead, 24 individual calls come in over a single T-1 line, or 23 calls come in over one Primary Rate Interface ISDN line. Modems or ISDN terminal adapters built into one-box remote access concentrators process the calls.

So what distinguishes one remote access device from the next? Scalability, for one thing. We surveyed 24 vendors for our interactive remote access Buyer's Guide. Eighteen entries are modular chassis-based servers and six are drop-in server boards. All have a minimum of 24 ports.

Of the dedicated remote access devices, the X1600 from Assured Access Technology (which Alcatel earlier this month announced plans to acquire) supports the most simultaneous sessions - a whopping 8,372. With a maximum port capacity of 2,016 analog or 364 PRI, the X1600 is designed for service providers. Also targeting this service provider tier is Lucent's PortMaster 4, which supports 864 simultaneous sessions.

The remainder of the chassis vendors, some of which also make boxes with ISP-type capacities, submitted products designed for mid-size to large enterprises. Four units support between 360 and 600 simultaneous users: 3Com's Total Control Multiservice Access Platform with HiPer Access System, Computone's DCS-5000, Ericsson Datacom Access' Tigris 3-Slot and Nortel Networks' 5399 Remote Access Concentrator. The rest fall between 60 and 240 simultaneous users per system.

Common ground

All the remote access boxes and board products in our Buyer's Guide support analog and digital ISDN dial-up connections. If remote offices or telecommuters have Basic Rate Interface lines, they can make 128K bit/sec connections; if not, they can use analog modems. All those surveyed support V.90, enabling 56K bit/sec downloads to remote users who have 56K bit/sec modems.

In addition, all the remote access devices can use a single phone number to handle analog modem and ISDN calls. The boxes detect whether a call is analog or ISDN and respond accordingly.

All the servers and server board products compress data traffic so remote users spend less time sending and receiving data, which can save on phone costs. Most of the vendors employ hardware and software compression; a handful support only software compression.

While a few years ago user name and password security was all that was available, today's remote access devices support many more options. All but six vendors support secure token cards. Another half-dozen support the emerging IP Security encryption standard.

All the chassis-based devices, as well as server cards from Brooktrout Technology and Interphase, can restrict remote-user access by a variety of methods, including user, group, time of day, call origin, session duration and line called. The rest of the board products depend on the server's operating system for access control.

Two-thirds of the chassis devices now support pass-through authentication to network operating system directories, such as Novell Directory Services, Windows NT domains, NetWare binderies and Lightweight Directory Access Protocol. This relieves managers from having to set authentication directly on the device, user by user.

Remote configuration and traffic monitoring capabilities are common to all the remote access devices we surveyed. Several also offer billing software so managers can monitor who is using the network the most and can charge back costs to individual departments.

Fault tolerance is a key concern for buyers of the chassis-based products. Look for hot-swappable boards, modems, WAN interfaces, power supplies, cooling fans and daughterboards. Among the vendors in our survey, 3Com, Assured Access Technology, ECI Telecom and Ericsson deliver all or most of these hot-swappable components.

For even more convenient failover protection, 10 devices offer "hot spare" cards in the rack. If a modem card fails, the server engages a spare card automatically or allows you to remotely activate a spare card; you don't need to go to the rack and physically swap components.

Build your own

Not everyone needs to buy a separate chassis to support remote access; another option is server cards. The cards plug into standard servers and, with appropriate software, convert them into remote access devices. Most of the cards feature onboard processors to handle calls without sapping the processing power of the server's CPU.

The number of dial-up sessions each card can support has been growing since these cards came on the scene in 1996. In our survey, Digi International hit the highest number with 48 analog connections or two PRI lines on a single card. Ariel, Interphase and Patriot Scientific are just behind

Digi with 46 or 47 user connections per card. You can use multiple cards in a single system; however, the maximum number of simultaneous users depends on the number of PCI slots available in the host server.

All the cards we surveyed work in servers running Windows NT Server, which makes managing them relatively simple for those who already have NT networks. In addition, Digi supports Unix and NetWare; Eicon Technology also supports NetWare.

Whichever way you decide to go, you have plenty of remote access options. Virtual private networks across the Internet may be gaining in popularity for remote access, but we expect direct-dial will be with us for quite a while.

RELATED LINKS Contact Senior Editor Tim Greene

Review: Remote access servers
Ascend's Max 6000 wins our Blue Ribbon award, although it isn't perfect. Network World, 3/29/99.

Interactive buyer's guide
Find the server that best matches your criteria, or compare two or more in several categories. Network World Fusion, 3/29/99.

RFP Central: Remote access
With the help of the Tolly Group, we solicited vendors for detailed remote-access proposals for a large enterprise. See the RFP and the responses we got. Network World Fusion, 3/29/99.